Since pineal region tumors are
among the most dangerous intracranial masses to excise, there has been an
ongoing debate for at least the last half-century concerning their surgical
management. The debate centers on whether it is in the patient's best interest
to explore these lesions at the time of their diagnosis, or whether the
obstructive hydrocephalus should be treated with a shunt and the posterior third
ventricular tumor irradiated without a tissue diagnosis-maneuvers which can be
carried out with a low morbidity and mortality rate.

Even though it has been
demonstrated repeatedly that it is feasible for highly experienced surgeons to
operate on lesions in the posterior third ventricle with a combined morbidity
and mortality rate of under 10 percent, whether all patients with a pineal
region tumor require surgical intervention remains a matter of judgment. For
example, patients in whom cytologic examination of the cerebrospinal fluid shows
malignant cells, patients with evidence of either spinal or extraneural
metastases, and patients harboring synchronous anterior and posterior third
ventricular tumors and in whom a tumor marker is elevated, most likely have a
germinoma or other malignant germ cell tumor and may not require direct
intervention.

In contrast to these cases,
there is a group of patients in whom surgical exploration is mandatory. These
are patients previously treated with a shunt and radiation therapy without a
tissue diagnosis who present with progressive neurological problems in the
presence of a functioning shunt. Such patients have often survived for a period
of years, and benign or relatively benign tumors are particularly frequent among
this select group. The controversy centers on the posterior third ventricular
lesion whose nature cannot be established preoperatively in spite of the best
available diagnostic modalities. In centers in Japan and in England these
patients are managed on a protocol of local field irradiation followed by
assessment by MRI as to whether tumor regression occurs. If this does occur, the
patients are subjected to whole-brain or whole-CNS irradiation. Among two groups
of patients treated in Tokyo between 1975 and 1988 there was a 73 percent 5-year
survival of those with histologically diagnosed germinomas and an 83 percent
5-year survival of those with suspected germinomas, outcomes which the
investigators reported to be statistically the same. Patients not responsive to
the 20 Gy local field irradiation are approached surgically. Among patients with
this group of nongerminomatous tumors, the 5-year survival rate was 28 percent.
Hoffman et al. have reported a 45 percent survival among patients with non-germ
cell tumors treated with surgery and radiation.

In the reported experience from
the Royal Marsden Hospital. 50 patients with pineal tumors were managed with an
initial 20 Gy local field irradiation. Responders were then given another 30 Gy
to the brain and to the spine. These authors reported an 81 percent 5-year
survival rate among patients with histologically diagnosed germinomas who
respond to 20 Gy irradiation, 64 percent 5-year survival among those with
non-germ cell tumors, and 18 percent 5-year survival among those with malignant
teratomas.

The malignant teratomas have a
particularly bad prognosis and are those tumors which often present with
elevations in the tumor markers and which recur rapidly following irradiation or
surgical excision. It is particularly in these tumors and in patients with tumor
recurrence that chemotherapeutic approaches seem to have a particular value.
Currently cisplatin-based therapy of VP-16 and cisplatin alternating with
vincristine, methotrexate, and bleomycin have been used to treat these cases
with encouraging results.